8-Iodo­quinolinium chloride dihydrate

Jung-Ho Son; James D Hoefelmeyer

doi:10.1107/S1600536808031528

. 2008 Oct 4;64(Pt 11):o2076. doi: 10.1107/S1600536808031528

8-Iodoquinolinium chloride dihydrate

Jung-Ho Son ^a, James D Hoefelmeyer ^a,^*

PMCID: PMC2959703 PMID: 21580941

Abstract

The title compound, C₉H₇IN⁺·Cl⁻·2H₂O, was obtained during the synthesis of 8-iodoquinoline from 8-aminoquinoline using the Sandmeyer reaction. The 8-iodoquinolinium ion is almost planar. Solvent water molecules and chloride ions form a hydrogen-bonded chain along the c axis via O—H⋯Cl links. The 8-iodoquinolinium ions, which are packed along the c axis with cationic aromatic π–π stacking (centroid–centroid distance = 3.624 Å), are linked to the chain via N—H⋯O hydrogen bonds.

Related literature

For the synthesis, see: Lucas & Kennedy (1943 ▶); Sandmeyer (1884 ▶). For a related structure, see: Son & Hoefelmeyer (2008 ▶). For related literature, see: Janiak (2000 ▶).

Experimental

Crystal data

C₉H₇IN⁺·Cl⁻·2H₂O
M _r = 327.54
Monoclinic,
a = 8.9600 (18) Å
b = 17.580 (4) Å
c = 7.1700 (14) Å
β = 97.13 (3)°
V = 1120.7 (4) Å³
Z = 4
Mo Kα radiation
μ = 3.07 mm⁻¹
T = 100 (2) K
0.71 × 0.67 × 0.54 mm

Data collection

Bruker SMART APEXII diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2006 ▶) T _min = 0.219, T _max = 0.288 (expected range = 0.145–0.190)
10655 measured reflections
2045 independent reflections
2040 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.019
wR(F ²) = 0.046
S = 1.25
2045 reflections
143 parameters
6 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.79 e Å⁻³
Δρ_min = −0.65 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808031528/ci2652sup1.cif

e-64-o2076-sup1.cif^{(15.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808031528/ci2652Isup2.hkl

e-64-o2076-Isup2.hkl^{(98.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1	0.82 (4)	2.03 (4)	2.755 (3)	147 (3)
N1—H1⋯I1	0.82 (4)	2.85 (4)	3.320 (2)	119 (3)
O1—H1A⋯O2	0.84 (1)	1.975 (12)	2.807 (3)	173 (5)
O1—H1B⋯Cl1ⁱ	0.83 (1)	2.75 (3)	3.382 (3)	134 (4)
O2—H2A⋯Cl1	0.84 (1)	2.435 (16)	3.237 (2)	160 (3)
O2—H2B⋯Cl1ⁱⁱ	0.84 (1)	2.379 (12)	3.211 (2)	170 (3)

Open in a new tab

Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

This work was supported by funding from the South Dakota 2010 Initiative, Center for Research and Development of Light-Activated Materials. Purchase of the X-ray diffractometer was made possible with funds from the National Science Foundation (EPS-0554609).

supplementary crystallographic information

Comment

8-Iodoquinoline is a starting material for the synthesis of 8-substituted quinoline derivatives. In this work, 8-iodoquinoline was synthesized starting from 8-aminoquinoline using the Sandmeyer reaction (Sandmeyer, 1884), following the synthesis of iodobenzene (Lucas & Kennedy, 1943). During its synthesis, two 8-iodoquinolinium salt crystals, 8-iodoquinolinium chloride dihydrate and 8-iodoquinolinium triiodide.THF (Son & Hoefelmeyer, 2008) were isolated. The synthesis, characterization and crystal structure of 8-iodoquinolinium chloride dihydrate (Fig. 1) are reported here.

The 8-iodoquinolinium ion is planar, with a maximum deviation of 0.069 (1) Å for the I1 atom. The C8—I1 bond length is 2.110 (3) Å and C9—C8—I1 angle is 121.09 (19) °. A short contact of 3.2083 (10) Å is observed between I1 and Cl1 ion at (1-x, 1-y, 1-z) that is likely due to ion-dipole interaction. The C8—I1···Cl1 angle is almost linear (177.13 (8)°).

Lattice water molecules and chloride ions form an extended hydrogen bonding chain network along the c axis (Table 1). Hydrogen bonding four-membered rings comprising O2 and Cl1 are alternately sharing edges with six-membered rings (in chair form) comprising O2, C1l and O1 along the c axis (Fig. 2). Atom O1 of the six-membered ring is hydrogen-bonded to atom N1 of the quinolinium ion. The 8-iodoquinolinium ions are parallel to each other and form a π-stack that is propogated along the c axis. The π-π stacking distance between the 8-iodoquinolinium rings is 3.624 Å (centroid-centroid distance between the 8-iodoquinolinium rings); there may be weak cationic repulsion between the rings (Janiak, 2000).

Experimental

A mixture of 8-aminoquinoline (10 g, 0.069 mol) and water (50 ml) was heated with stirring. The mixture was cooled in an ice bath and concentrated HCl (50 ml) was added to form a red solution. An ice-cooled NaNO₂ (7.8 g, 0.113 mol) solution in water (50 ml) was slowly transferred to the 8-aminoquinoline solution. A light brown precipitate was formed during the addition step but eventually it disappeared to form a reddish transparent solution. KI (17.9 g, 0.108 mol) dissolved in water (25 ml) was then added to the reaction mixture. Bubbles and brownish vapour evolved during the addition. The solution turned to dark brown with a black precipitate. The solution was then refluxed with a watch glass on top of the beaker, and it turned reddish brown with formation of a heavy organic layer; the black precipitate remained. After cooling and standing overnight, golden brown crystals of 8-iodoquinolinium chloride dihydrate had formed spontaneously in the solution. The mixture was neutralized upon addition of NaOH solution, which led to dissolution of the golden brown crystals and retention of the black precipitate. The liquid portion was separated from the black precipitate. 8-iodoquinoline was recoverd from the liquid portion upon extraction with toluene. Yield: 10.71 g of 8-iodoquinoline (61%). Physical data for 8-iodoquinolinium chloride dihydrate: m.p. 388-390 K (431-433 K after dehydration). ¹H NMR (methanol-d4): 7.638–7.716 (dd, 1H, quin CH), 8.144–8.214 (dd, 1H, quin CH), 8.313–8.360 (dd, 1H, quin CH), 8.605–8.647 (dd, 1H, quin CH), 9.179–9.228 (dd, 1H, quin CH), 9.253–9.288 (dd, 1H, quin CH). ¹³C NMR (methanol-d4): 90.253 (quin C8), 124.038 (quin CH), 131.224(quin CH), 131.475 (quin C9/10), 132.070 (quin CH), 139.889 (quin C9/10), 147.113(quin CH), 148.440 (quin CH), 149.608 (quin CH). Analysis calculated for C₉H₇ClIN (dehydrated): C 37.08, H 2.42, N 4.80%; found: C 36.76, H 2.40, N 4.85%.